Oh, good grief. They're not "conceding", they're rather transparently attempting to lower expectations, so that the next morning's headlines will be about Romney doing better than expected. The quote you cited makes exactly that point.
Romney is far enough behind that he needs something seen as big, dramatic, exciting
to shake up the race. The debates are pretty much his last chance for that. To get a big enough boost out of the first debate, he's having to lower expectations further than usual. This expectations game is always amusing, but Romney is carrying it to new lengths.